Mechanical oxidation of unsaturated polyesters

ABSTRACT

Liquid unsaturated polyester resins may be converted to millable compositions by blending the liquid polyester with a metallic drier and oxidizing the liquid mixture at elevated temperatures by mechanically mixing in the presence of an oxidizing atmosphere. A viscous gel forms on oxidation which, on cooling to room temperature, is suitable for compounding, milling and curing to form useful materials such as rubbery compositions, caulking compounds and resilient flooring.

United States Patent Harris 15] 3,673,138 [451 June 27, 1972 [54] MECHANICAL OXIDATION OF UNSATURATED POLYESTERS [72] Inventor: Thomas G. Harris, 110 Jackson Drive,

' Lancaster, Pa. 17603 [22] Filed: Sept. 14, 1970 21 Appl. No.: 72,152

[52] U.S. Cl. ..260/22 TN, 260/22 M, 260/40 R, 260/40 TN, 260/75 TN [51] Int. Cl. ..C08f 27/10, C08f27/22, C08g 17/14 [58] Field of Search ..260/75 T, 75 TN, 22 T, 22 M [56] References Cited UNITED STATES PATENTS 3,457,236 7/1969 Ehrhart et a1 ..260/75 2,877,203 3/1959 Forsythe et a1. ..260/75 2,974,112 3/1961 Forsythe et al. ..260/22 1,581,902 4/1926 Wright ,..260/75 1,901,374 3/1933 Luther et al.. ...260/75 2,975,071 3/1961 Ferrigno ..260/22 Primary Examiner-Donald E Czaja Assistant ExaminerRonald W. Griffin Attorney-William G. Taylor 57 ABSTRACT 1 Claim, N0 Drawings MECHANICAL OXIDATION OF UNSATURATED POLYESTERS BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a process whereby liquid unsaturated polyesters are mechanically oxidized to form useful millable compositions.

2. Description of the Prior Art Linoleum was-first prepared by allowing an unsaturated vegetable oil, such as linseed or chinawood oil, to slowly drip onto cloth or scrim, a countercurrent of air gradually oxidizing this. The gel-like material thus formed was referred to as cement" or beef." This material was then suitably compounded and placed upon a substrate after which it was pressed and cured.

As demand for linoleum increased, mechanical equipment was devised to handle the oxidation step, and the process came to be known as Mechanical Oxidation. This equipment conventionally consisted of a rotating drum holding the oil which was heated to an elevated temperature and through which a current of air was passed until the desired viscosity (determined by a penetration test) was reached. Other improvements in the processing of linoleum included the introduction of a metallic drier to accelerate oxidation and the incorporation of rosin as a viscosity depressant to allow extension of the oxidation. Replacement of the linseed and chinawood oils by more economical compositions occurred over the years, and one of the more successful commercial cements had the rosin chemically bonded to the oil.

SUMMARY OF THE INVENTION In accordance with this invention, 1 have discovered that liquid unsaturated polyester resins may be mechanically oxidized to produce millable compositions which may be further compounded and milled and subsequently cured to form useful materials such as rubbery compositions useful for such industrial applications as gaskets and resilient flooring products.

DESCRIPTION OF THE PREFERRED EMBODIMENT The liquid unsaturated polyester resins with which this invention is concerned comprise the reaction products of about 50 mol percent of an acid component; of which 30 to 50 mol percent is an aromatic dicarboxylic acid or its anhydride, including mixtures thereof, and of which to mol percent is an alpha-beta ethylenically unsaturated dicarboxylic acid or its anhydride, including mixtures thereof; and about 50 mol percent of diol component; of which 0 to 35'mol percent is an allyl unsaturated diol and of which 15 .to 50 mol percent is either a polyoxy alkylene diol, an alkylene diol, or mixtures thereof. Of the initial reactants, at least 4 and no more than 35 mol percent of said reactants must be either an alpha-beta ethylenically unsaturated dicarboxylic acid, its anhydride or mixtures thereof or an allyl unsaturated diol or a mixture of such unsaturated acid and unsaturated diol.

The unsaturated polyester resins which are the subject of this invention are obtained by condensation of the acids or anhydrides with the diols to obtain a polyester, preferably having a minimum molecular weight of 2,500. When desired, the polyester resins may be chain extended by reaction with diisocyanates. Chain extension may be accomplished by reaction with almost any diisocyanate such as 2,4 toluene-diisocyanate,

diphenylmethane diisocyanate and/or prepolymers obtained by reacting about 2 mols of such diisocyanate with one mol of u diol.

The polyester resins herein described are hydroxy terminated. The method of Ehrhart and Rohrer, U.S. Pat. No.

The aromatic dicarboxylic acids, their anhydrides (or dial-- kylesters) may be representated by the following formulas:

In the formula, R represents an alkyl radical of one to three carbon atoms. Examples of aromatic dicarboxylic acids, anhydrides and esterswhich are useful in forming the unsaturated polyester resins with which this invention is concerned are phthalic anhydride, o-phthalic acid, dimethyl terephthalate, isophthalic acid and terephthalic acid. Obviously, corresponding ring substituted aromatic dicarboxylic acids, anhydrides and esters might be substituted, in whole or in part. The aromatic dicarboxylic acid, anhydride and ester component may be comprised of a single acid, anhydride or ester or mixtures thereof.

Examples of alpha, beta ethylenically unsaturated dicarboxylic acids or anhydrides which are useful in forming the polyester resins with which this invention is concerned are maleic acid or its anhydride and fumaric acid.

The allyl unsaturated diol is a diol having allyloxy groups pendant to the diol chain and is generally of the formula:

wherein the hydroxyl groups are primary or secondary and wherein R is H or an alkyl group of from one to five carbon atoms which may be straight or branched chain; R, R, and R are alkylene groups of from one to five carbon atoms which may be straight or branched chain; m is equal to O or 1 and n is equal to O or 1. Examples of such glycols are trimethylolpropane monoallylether, glyceryl monoallylether, pentaerythritol diallyl ether, and erythrityl diallyl ether.

A polyoxyalkylene diol of the formula:

may be utilized. In this formula, R, R and R represent alkylene radicals of two to four carbon atoms which may be straight or branched chain and which may be the same or different. In the formula, 2:, y, and 1 represent integers, one or two of which may be 0, the integers representing x, y, z, and n are such that the molecular weight of the polyoxyethylene diol ranges from approximately 200 to 4,000. Mixtures of any of the above polyoxyalkylene diols may also be used.

More specifically, examples of the polyoxyalkylene diols having molecular weights of about 4,000 or lessare polyoxyethylene diols, which are also known as polyoxyethylene glycols, of the formula:

HO- CH CH 0 ,,l-l

wherein n is approximately an integer of from about 3 to approximately 69. These polyether diols are referred to as polyoxypropylene diols or polyoxypropylene glycols and are available under the Union Carbide trade name Niax Diol PPG, two examples of which are Niax Diol FPO-425 wherein n is approximately 7 and Niax Diol FPO-1,025 wherein n is approximately 17 to 18.

Other useful polyether diols are the polyoxytetramethylene diols which compounds are commercially available under the Quaker Oats Company trade name Polymeg. Copolyether diols, available commercially under the trade name Pluronics (Wyandotte Chemicals) are also useful.

The alkylene glycols useful in preparing the polyester resins -with which this invention is concerned are those of the formu- HO R OH wherein R is an alkylene radical of two to six carbon atoms which may be either straight chain or branched. Specific examples of these alkylene glycols are ethylene glycol, 1,2- propylene, 1,3-propane diol, 1,3-butane diol, 1,4-butane diol and neopentyl glycol.

In order to convert the liquid unsaturated polyester resin to a millable composition, the liquid polyester is conventionally treated in a rotating drum in which the liquid is heldwhile it is heated to an elevated temperature and through which a current of air is passed. Metallic driers, up to parts by weight, are preferably blended into the liquid polyester prior to or after introduction in the drum.

During oxidation, the liquid polyester resin is converted from a liquid form to a tough elastic polymer. The period of time necessary for the conversion is dependent upon the temperature to which the liquid is elevated, the amount and type of drier present and the temperature and amount of air or oxygen brought into direct contact with the liquid polyester. Of

- the driers utilized in the practice of the invention, manganese naphthenate and lead tallate are preferred.

In some of the following examples, it has been found that a slight degree of chain extension with a diisocyanate is desirable following the mechanical oxidation. The purpose of this reaction is to tie up loose saturated fragments that detract from the physical properties of the oxidized polyester.

The unsaturated polyesters of the examples which follow contain 0.03 percent by weight of tertiary butyl catechol which is utilized as an inhibitor, and the required oxidation time may be further regulated by varying the amount of this material.

' The following examples illustrate specific embodiments of the invention:

EXAMPLE 1 An unsaturated polyester comprising the reaction-product of the following:

and having an acid number of 0.8 and a hydroxyl number of 30.0 was initially blended with 0.03 percent by weight of 4 percent manganese naphthenate and mechanically oxidized by placing the liquid into a drum and rotating'at 60 rpm while passing dry hot (100 F.) air through the rotating drum. The blend or mix was reacted for minutes at a reaction temperature of about 200 F. The. oxidized product was discharged from the drum and, on cooling, formed a viscous gel which was compounded as follows on a two roll mill (210 F./ 190 F.) and sheeted thereon (R.T./l70 F.) to 0.120 inch gauge.

Ingredient Parts by Weight Polyester gel 100.00 Limestone (50 mesh) 20.35 Limestone (325 mesh) 60.61 Calcium metal silicate 40.69 Titanium dioxide 1 1.69 Tertiary butyl peroxyisopropyl carbonate 0.43

This sheet was cured by pressing at 350 F. and exerting 1,000 psi thereon to give a sheet 0. inch gauge having the proper- P sa oz in ablsl- EXAMPLE 2 An unsaturated polyester comprising the reaction product of the following:

and having an acid number of 1.0 and a hydroxyl number of 30.8 was blended with 0.03 percent by weight of 4 percent manganese naphthenate. The blended liquid was added to a drum and oxidized by rotating the drum at 60 rpm while passing dry hot (100 F.) air through the rotating drum. A reaction time of 100 minutes and a reaction temperature of 200 F. resulted in the conversion of the liquid polyester blend to a tough viscous gel which was discharged from the drum and compounded on a set of rolls (220 'F./200 F.) and sheeted (R.T./ F.

lngredients Parts by Weight Polyester gel 100.00 Wood flour 72.73 Limestone 48.92 Titanium dioxide v 38.09 Tertiary butyl peroxyisopropyl carbonate 0.43

The sheet thus formed was pressed at 350 F. and 1,000 psi to give a 0.090 inch resilient sheet usable as a floor covering and having the properties set forth in Table I.

EXAMPLE 3 An unsaturated liquid polyester comprising the reaction product of the following:

Reactant Mol Percent Phthalic anhydride 44.89 Maleic anhydride 5.1 1 Polyoxyethylene glycol (M.W. 400) 10.63 Ethylene glycol 39.37

Ingredients Parts by Weight Polyester gel 100.00 FEF Black 30.00 Stearic acid 1.00 Dicumyl peroxide (40% by weight in an 1.25

inert carrier The compounded polyester gel, when sheeted and cured seconds at 320 F.), formed a sheet having properties set forth in Table I1.

EXAMPLE 4 96.34 parts by weight of an unsaturated polyester formed from,

Reactant M01 Percent Phthalic anhydride 45.84 Maleic anhydride 4.16 Polyoxyethylene glycol (M.W. 400) Ethylene glycol were reacted with 1.38 parts by weight of toluene diisocyanate. This was then blended with 2.28 parts of a 16 percent lead tallate drier and mechanically oxidized at 240 F. Running time was 4 minutes. The polyester cement possessed a very slight tack and displayed a transition temperature of -1 6 C. it was compounded as follows:

sheeted, and cured 10 seconds at 320 F. The cured material showed properties listed in Table I1.

TABLE 11 Example 3 4 Tensile strength, psi 797 968 Elongation, 360 350 Hardness, Shore A 46 48 Gel content (Chloroform) 64 72 EXAMPLE 5 97.72 parts by weight of an unsaturated polyester of composition,

Reactant Mol Percent Phthalic anhydride 44.07 Maleic anhydride 5.93 Polyoxyethylene glycol (M.W. 400) 14.12 Ethylene glycol 3 5.88

acid number 1.05, and hydroxyl number. 22.10, were blended with 2.28 parts by weight of a lead tallate drier (2.35 percent lead tallate). Heat was applied and the whole heated to 240 F. at which point a current of air was passed through until a Mooney Viscosity of 10 was obtained.

At this point, 2.35 parts by weight of toluene diisocyanate were introduced dropwis'e. When addition was complete, the temperature was raised to 275 F. and held at this temperature for one hour.

0.3 parts by weight of tertiary butyl catechol were then added, thoroughly distributed, the whole discharged, and cooled. This was then compounded:

sheeted and cured 15 seconds at 315 F.

The cured material possessed properties as follows:

Tensile strength, psi 1092 Elongation, 160 Hardness, Shore A 59 Compression set (70 hours at 212 F.) 55 Transition temperature, C. l4 Gel content (Chloroform), 77

EXAMPLE 6 parts of an unsaturated polyester of the following composition,

Reactant Mol Percent Phthalic anhydride 45.70 Maleic anhydride 4.30 Polyoxyethylene glycol (M.W. 400) 21.13 Ethylene glycol 28.87

acid number 125, and hydroxyl number 22.55 were mechanically oxidized and then chain extended with 3.08 parts of toluene diisocyanate. Following compounding, sheeting and curing as in Example 5 an elastomer with the following properties was obtained:

Tensile strength, psi 821 Elongation, 300 Hardness, Shore A 45 Compression Set (70 hours at 212 F.) 65 Transition temperature, C. 20 Gel content (chloroform, 70) 69 .7. EXAMPLE 7 97.72 parts by weight of an unsaturated polyester of composition,

Mol Percent Reactant Phthalic anhydride 41.69 Maleic anhydride 8.31 Polyoxytetraethylene glycol (M.W. 624) 6.23 Ethylene glycol 43.77

acid number 0.76, and hydroxyl number 21.80; were blended with a lead tallate drier and mechanically oxidized at 200 F. Running time was 69 minutes.

The polyester cement" was compounded on a rubber mill,

phr

Polyester cement 100.00 FEF Black 30.00 Stearic Acid 1.00 Dicumyl peroxide (40%) 1.25

EXAMPLE 8 97.72 parts by weight of unsaturated polyester of composition,

Mol Percent acid number 0.58, and hydroxyl number 27.14, were blended with 2.28 parts by weight of a lead tallate drier, and mechanically oxidized at 240 F. Running time was 49 minutes.

EXAMPLE 9 An unsaturated polyester of the following composition,

Reactant Mol Percent Phthalic anhydride 50.00 Glycerol mono allyl ether 29.00 Polyoxyethylene glycol (M.W. 400) 10.50

Ethylene glycol displaying an acid number of 0.78 and an hydroxyl number of 30.61, was mechanically oxidized at 240 F. Running time was 74 minutes.

This example illustrates use of two types of unsaturation.

EXAMPLE 10 An unsaturated polyester of composition,

Reactant Mol Percent Phthalic anhydride 45.79 Maleic anhydride 4.21 Trimethylolpropane mono allyl ether 25.27 Polyoxyethylene glycol (M.W. 400) 10.68 Ethylene glycol 14.05

acid number 1.14, and hydroxyl number 40.95 was stabilized by the addition of 0.3 percent tertiary butyl catechol. This was later mechanically oxidized at 240 F. Running time was 2,500 minutes.

I claim:

1. A method for converting a liquid unsaturated polyester resin to a millable gum wherein the polyester is the reaction product of:

a. 30 to 50 mol percent of an'acid component which is a member selected from the group consisting of and mixtures thereof wherein R represents an alkyl radical of from one to three carbon atoms; and

b. O to 20 mol percent of an acid component which is a member selected from the group consisting of an alpha, beta ethylenically unsaturated dicarboxylic acid, an anhydride thereof and mixtures thereof; and

c. O to 35 mol percent of a diol component which is a member selected from the group consisting of a diol havinganallyloxy group pendant from the diol chain and mixtures thereof; and

cl. 15 to 50 mol percent of a diol component which is a member having an average molecular weight less than about 4,000 selected from the group consisting of a polyoxyalkylene diol, an alkylene diol of the formula l-lOROl-l wherein R is an alkylene radical of two to six carbon atoms, and mixtures thereof:

at least 4 mol percent and not more than 35 mol percent of said reactants being members selected from (b), (c) or mixtures thereof; the mole ratio of acid component to diol component is l to 1;

comprising mechanically oxidizing the liquid resin in an oxidizing atmosphere and in the presence of, based on parts by weight resin, up to 5 parts by weight metallic drier, at a reaction temperature in the range of 200 to 350 F. for a period of time sufficient to convert the liquid to a viscous gel, and chain-extending the oxidized polyester by reaction with a diisocyanate.

UNITED STATES PATENT OFFICE Certifcate Patent No. 3,673,138 Patented June 27, 1972 Thomas G. Harris Application having been made by Thomas G. Harris, the inventor named in the patent above identified, and Armstrong Cork Company, Lancaster, Pa., a corporation of Pennsylvania, the assignee, for the issuance of a certificate under the provisions of Title 35, Section 256, of the United States Code, adding the name of Charles Melvin Lindeman as a joint inventor, and a showing and proof of facts satisfying the requirements of the said section having been submitted, it is this 19th day of February 1974, certified that the name of the said Charles Melvin Lindeman is hereby added to the said patent as a joint inventor with the said Thomas G. Harris.

FRED W. SHERLING Associate Solicitor. 

